Planning Permission and Building Regulations Sign-Off: What UK Buyers Should Check on an Extended Home
If a home in England has an extension, loft conversion or converted garage, you should ask two separate questions: did the work have planning permission or fall within permitted development, and was it signed off under building regulations? They are different approvals, and a missing one can slow a purchase or a later sale.
This Banke UK guide explains the difference in plain English and lists the documents to ask your solicitor to request. Rules differ between England, Scotland, Wales and Northern Ireland, so confirm the local position for your property.
The Short Answer
Planning permission is about whether the work was allowed to be built at all. Building regulations are about whether it was built safely, for example the structure, fire safety, insulation and electrics. A home can have one without the other. Buyers usually want evidence of both for any significant work, and a solicitor can raise what is missing before exchange of contracts.
Planning Permission and Permitted Development
Some smaller changes do not need a full planning application because they fall within permitted development rights. Those rights have conditions and limits, and they can be removed in some areas, for example by conservation area status or earlier planning conditions. If the seller says the work was permitted development, ask whether a lawful development certificate was obtained. It is the clearest proof, and its absence is not automatically a problem but is a question to ask.
Building Regulations Sign-Off
Most extensions, loft conversions and structural changes need building regulations approval and a final certificate or completion certificate from the local authority or an approved inspector. Electrical work and some other trades may have separate certificates from registered installers.
Documents to Ask For
- The planning decision notice, or the lawful development certificate
- The building regulations completion certificate, or a regularisation certificate if it was obtained afterwards
- Electrical installation certificates and, for boilers, installer certificates
- Structural calculations or engineer's letter for removed walls
- Any guarantee for the roof, damp-proofing or windows
If Something Is Missing
- Ask the seller to obtain it before exchange, for example a retrospective approval.
- Indemnity insurance is sometimes offered for a missing approval. A solicitor should explain what it does and does not cover, and a lender may have its own view.
- Adjust the price or walk away if the risk is bigger than the saving.
- Lenders may refuse or delay if the paperwork is missing, so tell your mortgage broker early.
A Surveyor Helps
A surveyor will often notice work that does not look right. See our guide to RICS home survey levels 1, 2 and 3 to choose the right depth, and ask the surveyor to comment on any extension.
Plans for Your Own Work
If you intend to extend after you buy, check the same two approvals before you start, and remember that leasehold flats usually need the landlord's permission as well.
To discuss a UK purchase from overseas, contact the Banke UK team.
This article is general, evergreen information and does not quote current rates, fees or thresholds. Rules and procedures change, so confirm the current position with the relevant authority or a qualified professional before you commit money. It is not legal, tax or financial advice.